qt-everywhere-src-5.14.1/qtdoc/doc/src/portingcppapps_toqt5.qdoc

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/*!
\page portingcppapp.html
\title Porting C++ Applications to Qt 5
\brief Provides instructions to migrate a Qt 4 C++ application to Qt 5.

This topic talks about the Qt Widgets changes in Qt 5. The
following step-by-step instructions take you through the changes required to
port the \l{Animated Tiles Example}{Animated Tiles} application to Qt 5:

\list 1
   \li Open the Animated Tiles project using Qt Creator.
   \li Edit \c {main.cpp} and replace the \c {#include <QtGui>} instance with
       \c {#include <QtWidgets>}.
       The Perl-script \c fixqt4headers.pl can be used to scan the source files
       of a project and perform the replacements.
   \li Edit the \c {animatedtiles.pro} and add \c {QT += widgets} towards the
       end of the file.
       \note \l{Qt GUI} is included by default in all Qt applications unless excluded using the \c {QT -= gui} directive in the \c{qmake} project file.
   \li Save the changes and run the application.
\endlist

Once you see the application running, check whether it behaves as expected.

\image animatedtiles_snapshot.png "A snapshot of the \c animatedtiles application running on Ubuntu v12.04"

It is also possible to keep the project compiling with Qt 4 and Qt 5. This requires:

\list 1
   \li Omitting the module name from all includes by running the
       \c fixqt4headers.pl script with the \c --strip-modules option.
   \li Adding scopes depending on the version of Qt to the \c{.pro} files:
       \code
       greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
       \endcode
   \li Introducing \c #if scopes around code using modified API:
       \code
       #if QT_VERSION >= 0x050000
           headerView->setSectionResizeMode(QHeaderView::ResizeToContents);
       #else
           headerView->setResizeMode(QHeaderView::ResizeToContents);
       #endif
       \endcode
\endlist

if you are using Qt WebKit, see
\l{Porting from Qt WebKit to Qt WebEngine}{Qt WebKit to Qt WebEngine} porting
instructions.

\section1 Related Topics
\list
\li \l {C++ API Changes}
\li \l {Porting QML Applications to Qt 5 Example}
\li \l {Qt Examples And Tutorials}
\endlist
*/